Datadef

When: read once before your first canvas_* call, to build or to edit. Datadef's standard for a readable diagram (size, edge discipline, nested zones, notes) and the tool workflow: which canvas_* tool to use when, batching, laying out once, checking with canvas_view. It is the same standard Datadef's own generator follows, so a diagram you build by hand comes out indistinguishable from a generated

When: Use when you want a flat list of every node, edge and zone. canvas_view shows the same ids as a zone tree with positions and defects, and is usually the better first read. Get an overview of the current canvas: zones as a nested tree in reading order, every node with its id, type, icon and family, all connections with labels, and every note in full. Call this first, before any edit, so you

When: Use before changing a node's fields or columns, to see everything it carries: columns, metadata, owners, neighbours. Get full detail for specific nodes: all columns with types and keys, metadata, schedule, formula, owners. Use before modifying a node so you preserve fields you are not changing. Batch: `nodes` (up to 10) takes a list; put every item in one call rather than one call per item

When: Use before adding nodes that should show a vendor logo (Snowflake, Kafka, Power BI) and you are unsure of the icon id. Find icon ids in Datadef's library (2000+ cloud and data-tool logos) by product name, e.g. "Amazon Aurora PostgreSQL", "k8s", "Azure Event Hubs". Pass `queries` to look up many names in one call (best id per name); pass `query` for the top matches of one name. Scores: 90+ s

When: Use only for a precise manual placement the user asked for: exact x/y/width/height per node. To check a layout, canvas_view is faster and already reports overlaps. Get exact geometry: every node's position and size in canvas units, the overall canvas bounds, and any nodes that overlap each other. Call this before moving, resizing, or placing anything precisely — positions are meaningless

When: Use to add components (tables, pipelines, sources, consumers, service icons), each placed in its zone with `group`. Add one or more nodes to the canvas. Batch every node you want in a single call. Positions are assigned by canvas_layout_canvas afterwards — never set them yourself. Batch: `nodes` (up to 40) takes a list; put every item in one call rather than one call per item. Operates

When: Use only when the user wants a node at a specific position, outside the automatic layout. Otherwise use canvas_add_nodes. Add a single data node at an exact position, without connecting it to anything. Use when the user wants something placed somewhere specific, or when you will wire it up yourself afterwards. For building out a connected diagram, canvas_add_nodes is better — it batches a

When: Use for any in-place change: rename a node or zone (it keeps its size and contents), edit a note's text, recolour (`color: "green"`, `fill`, `family`), change a zone's style, swap an icon, or change a data node's type; fields you do not pass stay as they are. Many nodes in one call. Change existing nodes, zones or notes in place: rename (a zone keeps its size and contents), edit a note's te

When: Use when one component changes identity or type (Redshift becomes Snowflake, a card becomes a service icon). The node keeps its id, connections, lineage, zone, position and fields. Turn a node into a different component in place — Redshift becomes Snowflake, a batch job becomes streaming. It keeps its id, every connection and lineage row, its zone, position, owners, schedule, colours and

When: Use to delete nodes and their edges. Removing a zone keeps its contents (they move up to the parent, same place on screen): that is how to ungroup. Pass keepChildren:false only to delete the zone with everything inside it. Delete nodes, notes or zones, with every edge and lineage row touching them. Removing a zone keeps its contents by default: they move up to the zone's parent and stay whe

When: Use to draw the flows that genuinely move data between two nodes. Never connect a zone: connect a node inside it. Draw edges (arrows) between nodes to show how data flows. Label an edge only when the reader could not guess what it does ("CDC", "hourly batch"); obvious flows and dimensional joins read better unlabelled. Edges always render with an arrowhead at the target; bidirectional adds

When: Use to relabel, retype, restyle (dashed, colour), reverse, put arrowheads on both ends, or re-point an existing edge, instead of disconnecting and reconnecting it. Change existing connections in place: relabel, retype, restyle (solid/dashed/dotted, colour), reverse the direction, put arrowheads on both ends, or re-point one end to another node. Identify each edge by source and target, or by

When: Use to delete specific edges between two nodes. Remove edges, given as source and target, or as an edge id / "Source -> Target" string in `edge`. Batch: `edges` takes a list; put every item in one call rather than one call per item. Operates on one Datadef diagram, named by diagram_id. Returns compact JSON: the ids it created, changed or removed, the diagram revision, a one-line summary

When: Use `mode: "merge"` to add or update (renameTo) a few columns, `mode: "remove"` to drop some, or the default replace for the full list. Columns that stay keep their ids and lineage. Change a table's columns. mode "merge" adds new columns and updates (or renames, with renameTo) the ones you name, leaving the rest alone — use it to add one column. mode "remove" deletes the named columns onl

When: Use to create a zone (a layer, domain, stage or boundary), nested with `parentGroup`, optionally moving existing nodes into it: the zone is drawn around them where they are, inside the zone they already share. Create a labelled zone (e.g. "Bronze Layer", "Ingestion") and optionally move nodes into it. The zone is drawn around the nodes where they already are, so nothing moves on screen; it

When: Use to move existing nodes or zones into another zone (they are placed inside it and the zone grows to fit), or out of every zone with group null. A zone cannot move into its own sub-zone. Move existing nodes or zones into an existing zone, or out of every zone (group: null). They keep their place on screen when they already sit inside the zone; otherwise they are placed inside it and the z

When: Use to record which source columns produce which target columns. No line is drawn. Record column-level lineage: which source column produces which target column, and how. This is what makes the diagram queryable for impact analysis, so add it for every real transformation. canvas_remove_lineage undoes it. Batch: `links` (up to 100) takes a list; put every item in one call rather than one c

When: Use to delete lineage rows between two nodes (one column pair, or all rows between them). Lineage pointing at deleted nodes or columns is cleaned automatically. Delete lineage rows between two nodes: one column pair, or every row between the two nodes when no column is given. Lineage pointing at deleted nodes or columns is cleaned automatically and never needs this. Batch: `links` (up to 1

When: Use for a note that tells the diagram's reader a decision, constraint or gotcha. Pass `anchor` (the node or zone it explains) and it is placed beside it, no coordinates needed. To edit a note's text use canvas_update_nodes. Add a text note: a caption, a callout, a note explaining a decision. Give `anchor` (the node or zone it explains) and the note is placed beside it, clear of other conten

When: Use rarely: a pointer or highlight the user asked for. Never as a backdrop; zones are the containers. Place a rectangle, circle, arrow, or line as a visual annotation — a divider, a highlight. Shapes are drawings: they connect nothing (use canvas_connect_nodes for arrows between nodes) and they are not zones (use canvas_group_nodes). Batch: `shapes` (up to 20) takes a list; put every ite

When: Use after the final layout, where one arrow should stand for a bundle of identical flows (zone to zone). Draw one large labelled arrow SHAPE between two areas of the diagram — "ingest", "serve", "publish". It is a drawing, not a connection: it links nothing and moves with nothing. To connect nodes use canvas_connect_nodes; never replace existing edges with this. Position it in the gap bet

When: Use after the final layout to mark nodes that belong together without moving them into a zone. Regions do not move with layout. Draw a labelled translucent area behind existing nodes to show they belong together, without reparenting them. Use this when the grouping is a reading aid rather than real containment, when areas would need to overlap, or when a node belongs to two ideas at once â€

When: Use when the diagram feels dense or the user asks to simplify. It changes nothing; it reports what could collapse. Report where this canvas could be collapsed — groups of similar nodes that could become one summary node — without changing anything. Use it to decide whether the diagram is denser than it needs to be. Density is not automatically a problem: keep the detail when the detail

When: Use to merge several similar nodes into one while keeping their connections, usually after canvas_suggest_simplifications. Merge several nodes into one summary node, keeping every connection. Use when a set of near-identical objects adds length without adding meaning — eight staging models that all behave the same become "stg_* (8)". Do not use when the individual objects are what the rea

When: Use only when the user asked for a specific placement. Moving a zone moves its children; never move the children as well. Set node positions precisely. Use absolute x/y to place something exactly, or dx/dy to nudge it. Coordinates are absolute canvas units (same space canvas_measure_canvas reports). Moving a group moves its children with it — do not also move those children in the same ca

When: Use only when the user asked for a specific size. Set the width and height of nodes. Mostly for shapes, text boxes, and group zones — data nodes size themselves from their content, and resizing one can clip what it displays. Batch: `resizes` (up to 40) takes a list; put every item in one call rather than one call per item. Operates on one Datadef diagram, named by diagram_id. Returns c

When: Use only when the user asked for alignment that layout does not give. Align nodes to a shared edge or centre line, or space them evenly. Cleaner and far more reliable than computing coordinates by hand. Batch: `nodes` (up to 40) takes a list; put every item in one call rather than one call per item. Operates on one Datadef diagram, named by diagram_id. Returns compact JSON: the ids it cr

When: Use once, after the structure (zones, nodes, edges) is complete, not after each change. With no arguments it only places what was added or changed; nothing else moves. Set mode "full", direction (LR/TB/RL), spacing (compact/normal/airy), fit (page-portrait/page-landscape/slide-16:9/square) or zone only when the user asked for a different layout. Position what you added or moved, or re-arran

When: Use before you finish: broken references and icons, nodes outside their zone, overlapping zones or nodes. Loops are reported as information only. Check your work: broken references, broken icons, nodes sticking out of their zone, overlapping zones or nodes, unconnected or unfed nodes. By default it reports only issues in what you changed in this session (scope "changed"); scope "all" checks

When: use to see a diagram before you edit it and after each round of changes; this is how you check your work. It answers in milliseconds from the saved diagram, where export_diagram starts a browser for 6-10 s. Returns a text map: the zones as a tree, each with its place on a coarse grid (r1 = top row, c1 = left column) and its nodes (label, type, icon, #id), then the edges, then the checks a r

When: use whenever you would otherwise make several canvas_* write calls in a row, above all with tools that take one item per call: create every zone (group_nodes), convert many nodes (replace_node), set several tables' columns (set_columns). Eighteen zone creations or thirty-five replacements become one call and one save. Each operation is {"tool": "<canvas tool, with or without the canvas_ pre

When: use when Datadef's own model should design a whole new diagram from a description or a pasted schema. To build it yourself step by step, use create_blank_diagram; to change an existing diagram, canvas_view and the canvas_* tools, or edit_diagram. Generates a professional data architecture diagram from a description and saves it to the user's Datadef account. Use it for any data-shaped diagr

When: use when you will build the diagram yourself with the canvas_* tools, because you want control over the result or already know the architecture from the conversation. Use create_diagram instead when Datadef's model should design the whole thing from a prompt. Creates an empty diagram and returns its diagram_id. No AI generation runs: you draw it. Call get_design_guide first: it is the stand

When: use to find the id of an existing diagram before viewing, editing or exporting it. Lists the diagrams in the user's Datadef account, most recently updated first. Next: canvas_view with the diagram_id to see it.

When: use to show the user a diagram (it attaches a rendered PNG and a markdown image line, 6-10 s), or to poll a diagram that create_diagram or edit_diagram is still working on. To check your own edits, canvas_view is faster and reports overlaps. Returns every node with its type and columns, every connection and the zones, plus whether a generation or edit_diagram run is still in progress. Next

When: use for a large change you can describe in words better than you can make it tool by tool: "reorganise this into bronze, silver and gold", "rebuild the consumption side from this spec", "add owners and schedules everywhere". For a precise change (rename, add a node, rewire an edge), the canvas_* tools are faster and exact. Datadef's own editing agent carries out the instruction: add nodes,

When: use to give the user an image of a diagram, or a link to download, attach or embed one. Not to check your own edits: a render starts a browser (6-10 s), while canvas_view answers in milliseconds and reports overlaps. Renders a diagram to PNG or JPEG. Returns the image inline AND a short-lived signed download URL. Use the inline image to show the diagram; use the URL when the user wants to s

For a diagram that was created from a connected git repository: which repo and branch or tag it tracks, when it last synced, the commit it reflects, and whether daily sync is on. Use repo_refresh to sync it now. Only the owner of the repository connection can use this.

Re-sync a repo-linked diagram from the current state of its repository. If the tracked branch or tag has not moved since the last sync, nothing changes. If it has, the diagram is REGENERATED from the repository, which replaces manual canvas edits. Only the owner of the repository connection can use this.